Floor-planning technique applied to circuit design in which a circuit is divided automatically into sub-circuits that are equally matched with efficiently arranged physical blocks

ABSTRACT

The invention provides a floor planning technique by which physical blocks having areas sufficiently matching with actual sub circuits can be produced automatically and also a physical block of a shape other than a rectangle can be produced using a very simple technique. To this end, a floor planning apparatus of the invention includes a circuit unit recognition section for recognizing circuit units which compose each of the sub circuits, a part information storage section for storing, for each of the circuit units, numbers of parts of different part types which compose the circuit unit, a part number calculation section for acquiring, for each of the different part types, the numbers of the parts composing the circuit units recognized by the circuit unit recognition section from the part information storage section and calculating, for each of the different part types, total numbers of the parts in each of the sub circuits, and an area calculation section for calculating and determining an area of the physical block based on the total numbers of the parts calculated for each of the different part types by the part number calculation section. The invention can be applied to designing of a circuit such as an LSI (Large Scale Integration) and a PCB (Printed Circuit Board).

BACKGROUND OF THE INVENTION

1) Field of the Invention

This invention relates to a technique applied to designing of a circuitsuch as an LSI (Large Scale Integration) or a PCB (Printed CircuitBoard).

It is a common practice to perform, after logical designing, floorplanning in order to mount a result of the logical designing. While alsoit is a common practice to temporarily mount a result of logicaldesigning to verify the same and feed back a result of the verificationto the logical designing, also upon such temporary mounting, floorplanning is performed.

A result of logical designing of a design object circuit is normallydivided into a plurality of circuit parts of sizes which are easy tohandle. The circuit parts are called sub circuits (or divided circuits).Then, in the floor planning, physical blocks having areas necessary tomount the sub circuits in a mounting region are determined first, andthen the physical blocks determined corresponding to the sub circuitsare arranged in the mounting region.

The present invention relates to an apparatus for and a method ofexecuting such floor planning as described above and also to acomputer-readable recording medium on which a floor planning program forrealizing the apparatus and the method is recorded.

2) Description of the Related Art

Usually, floor planning is performed upon mounting of a circuit afterlogical designing or upon temporary mounting of a circuit for verifyinga result of logical designing.

As described above, a result of logical designing of a design objectcircuit is normally divided into a plurality of sub circuits (dividedcircuits) of sizes which are easy to handle. Each sub circuit iscomposed of a plurality of circuit units (which may be hereinafterreferred to as minimum circuit units). Where the design object circuitis an LSI, the minimum circuit unit is a cell.

In an ordinary floor planning apparatus, the shapes of physical blocksonto which sub circuits are to be mounted in a mounting region arelimited to rectangles, and the area (size) of each physical block iseither designated by an operator (a user or a designer) or automaticallyproduced based on a duty (=circuit area/region area) and an aspect ratiodesignated by an operator, and the theoretical shape of the physicalblock is displayed. Here, for the circuit area, a sum total of the areasof a plurality of minimum circuit units (for example, leaf cells) whichcompose each sub circuit.

Thereafter, in the ordinary floor planning apparatus, the physicalblocks (rectangles) whose shapes/areas are set for the individual subcircuits are arranged as they are in the mounting region to determinethe arrangement positions of them. In this instance, the physical blocksare usually arranged such that they do not overlap with any otherphysical block. For example, where ten physical blocks B1 to B10 are setas shown in FIG. 8, they are arranged, for example, in such a manner asshown in FIG. 9 in a mounting region.

However, when the areas of the physical blocks are determined asdescribed above, if an operator designates the areas of the physicalblocks one by one for the sub circuits, not only is much time requiredfor the floor planning and a much burden is imposed on the operator, butalso the floor planning is inefficient. Thus, it is demanded to automatethe determination of the areas of physical blocks.

Further, where the ordinary technique wherein the areas of physicalblocks are automatically produced and determined as described above isemployed, only the shapes/areas are automatically produced bydesignating the duties and the aspect ratios determined taking the areasof minimum circuit units into consideration. The area of a physicalblock should be determined roughly in accordance with a number of parts(for example, basic cells) of minimum circuit units of the physicalblock. The area, however, is influenced, in the case of an LSI, not onlyby basic cells, but also by wiring regions of the sub circuit (thenumber of areas in which the wiring region is included) pins, networks,fan-outs and so forth. Accordingly, the area of a physical blockdetermined based on a duty determined taking only the areas of basiccells of leaf cells (minimum circuit units) into consideration is notconsidered to sufficiently match an actual sub circuit, but matters inregard to the accuracy and may possibly give rise to some trouble whenmounting designing is performed so as to arrange circuit parts in a highdensity.

Further, since physical blocks are usually limited to rectangles andarranged such that they do not overlap with any other physical block asdescribed above, if physical blocks B1 to B10 of various shapes/areasare arranged as seen in FIG. 9, then it is impossible to fully fill upgaps (refer to slanting line regions in FIG. 9) among the physicalblocks B1 to B10, and it cannot be avoided that a plurality of non-usedregions appear in the mounting region, which makes it difficult toefficiently use the mounting region. The presence of such non-usedregions increases the distances between the physical blocks andconsequently increases the lengths of wiring lines between the physicalblocks, and this has an influence upon delays of signals and besidesgives rise to such a subject that it disturbs high density integrationof circuits. Further, the non-used regions appear in most cases aselongated rectangles, and physical blocks which can be arranged in thenon-used regions are limited very much in terms of the size and theshape. Consequently, even if it is tried to arrange physical blocks inthe non-used regions, those physical blocks which can be arranged arelimited.

It seems possible to use, without limiting the shapes of physical blocksto rectangles, various shapes (polygons). In this instance, suchsubjects as described above are not invited. However, in order todesignate a shape other than a rectangle, it becomes necessary tosupport plotting of a polygon, and this makes operation by an operatorvery complicated.

For example, if it is tried to set the shape of a physical block to ashape other than a rectangle, then an operator must perform suchoperation as to first perform an operation for plotting a polygon andthen perform, since a duty is fed back as a result of the operation,re-plotting taking the duty into consideration.

Accordingly, from the reason that, upon production of a shape of aphysical block from the area of the physical block, the shape can bedetermined very simply, the shapes to be produced by an ordinary floorplanning apparatus are in most cases limited to rectangles.

However, in order to eliminate the problem of signal delays withcertainty while an increase in density of circuitry in recent years issatisfied, it is intensely demanded to make it possible to produce aphysical block of a shape other than a rectangle using a very simpletechnique.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a floor planningapparatus and a floor planning method as well as a computer-readablerecording medium having a floor planning program recorded thereon bywhich physical blocks having areas sufficiently matching with actual subcircuits can be produced automatically and also a physical block of ashape other than a rectangle can be produced using a very simpletechnique to allow physical blocks to be arranged efficiently in amounting region and eliminate the problem of signal delays withcertainty while satisfying an increase in density of circuitry.

In order to attain the objects described above, according to an aspectof the present invention, there is provided a floor planning apparatuswhich determines, in order to mount a design object circuit, for each ofsub circuits obtained by dividing the design object circuit, a physicalblock having an area necessary to mount the sub circuit in a mountingregion and arranges the physical blocks in the mounting region,comprising a circuit unit recognition section for recognizing circuitunits which compose each of the sub circuits, a part information storagesection for storing, for each of the circuit units, numbers of parts ofdifferent part types which compose the circuit unit, a part numbercalculation section for acquiring, for each of the different part types,the numbers of the parts composing the circuit units recognized by thecircuit unit recognition section from the part information storagesection and calculating, for each of the different part types, totalnumbers of the parts in each of the sub circuits, an area calculationsection for calculating and determining an area of the physical blockbased on the total numbers of the parts calculated for each of thedifferent part types by the part number calculation section, atheoretical shape calculation section for calculating a theoreticalshape of the physical block based on the area of the physical blockdetermined by the area calculation section and a shape productionparameter set in advance for the physical block, a display controlsection for causing a display section to display the physical blockhaving the theoretical shape obtained by the theoretical shapecalculation section, an arrangement section for arranging the physicalblock having the theoretical shape obtained by the theoretical shapecalculation section at a designated position in the mounting region, anda shape modification section for deleting, when the physical blockarranged by the arrangement section overlaps with another one of thephysical blocks arranged already, an overlapping portion from one of thearranged physical block and the already arranged physical block andmodifying the shape of the one physical block whose overlapping portionis deleted so that the one physical block may have an area equal to thearea determined by the area calculation section and may not overlap withthe other one of the two physical blocks from which the overlappingportion is not deleted.

The floor planning apparatus may be constructed such that it furthercomprises a priority order storage section for storing a priority orderset in advance for the individual physical blocks, wherein the shapemodification section determines one of the physical blocks from whichthe overlapping portion is to be deleted to modify the shape of thephysical block based on the priority order stored in the priority orderstorage section.

Alternatively, the floor planning apparatus may further comprise a modesetting section for setting a mode in which modification to the shape ofany already arranged physical block by the shape modification section isinhibited, or the theoretical shapes of the physical blocks calculatedby the shape modification section may be limited to rectangles.

As a further alternative, the floor planning apparatus may beconstructed such that it further comprises an area calculationexpression storage section for storing an area calculation expression tobe used for calculation of the areas of the physical blocks, and thearea calculation section re-calculates, upon division modification orlogical modification of the design object circuit, the areas of thephysical blocks using the area calculation expression stored in the areacalculation expression storage section.

Otherwise, the floor planning apparatus may further comprise anevaluation expression storage section for storing an evaluationexpression to be used for evaluation of the areas/shapes of the physicalblocks, an evaluation section for evaluating the areas/shapes of thephysical blocks based on the evaluation expression stored in theevaluation expression storage section, and a display control section forcausing the display section to display a result of the evaluation by theevaluation section.

According to another aspect of the present invention, there is provideda floor planning method for determining, in order to mount a designobject circuit, for each of sub circuits obtained by dividing the designobject circuit, a physical block having an area necessary to mount thesub circuit in a mounting region and arranging the physical blocks inthe mounting region, comprising the steps of recognizing, for each ofthe sub circuits, circuit units which compose the sub circuit,acquiring, for each of the circuit units recognized, numbers of parts ofdifferent part types which compose the circuit unit and calculating, foreach of the different part types, total numbers of the parts in each ofthe sub circuits, calculating and determining an area of the physicalblock based on the total numbers of the parts calculated for each of thedifferent part types, calculating a theoretical shape of the physicalblock based on the area of the physical block and a shape productionparameter set in advance for the physical block, causing a displaysection to display the physical block having the calculated theoreticalshape, and deleting, when the physical block having the calculatedtheoretical shape is arranged at a designated position in the mountingregion, if the physical block overlaps with another one of the physicalblocks arranged already, an overlapping portion from one of the newlyarranged physical block and the already arranged physical block andmodifying the shape of the one physical block whose overlapping portionis deleted so that the one physical block may have an area equal to adetermined area and may not overlap with the other one of the twophysical blocks from which the overlapping portion is not deleted. Inthis instance, one of the physical blocks from which the overlappingportion is to be deleted to modify the shape of the physical block maybe determined based on a priority order set in advance for theindividual physical blocks.

According to a further aspect of the present invention, there isprovided a computer-readable recording medium having a floor planningprogram recorded thereon for causing, in order to mount a design objectcircuit, a computer to determine, for each of sub circuits obtained bydividing the design object circuit, a physical block having an areanecessary to mount the sub circuit in a mounting region and arrange thephysical blocks in the mounting region, the floor planning programcausing the computer to function as a circuit unit recognition sectionfor recognizing circuit units which compose each of the sub circuits, apart number calculation section for acquiring, for each of the differentpart types, numbers of parts composing the circuit units recognized bythe circuit unit recognition section and calculating, for each of thedifferent part types, total numbers of the parts in each of the subcircuits, an area calculation section for calculating and determining anarea of the physical block based on the total numbers of the partscalculated for each of the different part types by the part numbercalculation section, a theoretical shape calculation section forcalculating a theoretical shape of the physical block based on the areaof the physical block determined by the area calculation section and ashape production parameter set in advance for the physical block, adisplay control section for causing a display section to display thephysical block having the theoretical shape obtained by the theoreticalshape calculation section, an arrangement section for arranging thephysical block having the theoretical shape obtained by the theoreticalshape calculation section at a designated position in the mountingregion, and a shape modification section for deleting, when the physicalblock arranged by the arrangement section overlaps with another one ofthe physical blocks arranged already, an overlapping portion from one ofthe newly arranged physical block and the already arranged physicalblock and modifying the shape of the one physical block whoseoverlapping portion is deleted so that the one physical block may havean area equal to the area determined by the area calculation section andmay not overlap with the other one of the two physical blocks from whichthe overlapping portion is not deleted. In this instance, when the floorplanning program causes the computer to function as the shapemodification section, the floor planning programs may cause the computerto determine one of the physical blocks from which the overlappingportion is to be deleted to modify the shape of the physical block basedon a priority order set in advance for the individual physical blocks.

With the floor planning apparatus and the floor planning method as wellas the computer-readable recording medium having a floor planningprogram recorded thereon according to the present invention describedabove, the following advantages can be anticipated.

(1) For example, where the design object circuit is an LSI, the area ofa physical block can be determined automatically taking not only basiccells but also wiring line regions, pins, networks, fan-outs and soforth into consideration as parts which form circuit units. In short, aphysical block having an area matching sufficiently with an actual subcircuit can be produced automatically, and upon mounting designing,circuit parts can be arranged in a high density without giving rise to aproblem in terms of the accuracy.

(2) Since a theoretical shape of a physical block is calculatedautomatically based on the area of the physical block determinedautomatically and a shape production parameter set in advance for thephysical block and a result of the calculation is displayed on thedisplay section, the operator who refers to the display section canconfirm the physical block having the area and the theoretical shapedetermined automatically.

(3) When a physical block is arranged at a designated position in amounting region, if it overlaps with another physical block arrangedalready, then the overlapping portion is deleted from either one of thenewly arranged physical block and the already arranged physical block,and the shape of the physical block from which the overlapping portionis deleted is modified to secure a predetermined area. Consequently,also a physical block of a shape other than a rectangle can be producedautomatically. Accordingly, while the shape of each physical block ishandled as a rectangle at all in operation, a shape other than arectangle can be provided as an actual shape to the physical block.Accordingly, physical blocks can be arranged very efficiently in themounting region, and also the problem of signal delays can be eliminatedwith certainty while satisfying high density arrangement of circuits.

(4) Where the mode in which shape modification to a physical blockarranged already is inhibited can be set, execution of uselesscalculation upon determination of a shape during editing can beinhibited.

(5) Since the theoretical shapes of the physical blocks are limited torectangles, calculation and determination of theoretical shapes of thephysical blocks can be performed very readily, and the time required forcalculation can be reduced remarkably.

(6) Upon division modification or logical modification to a designobject circuit, by re-calculating the area of a physical block using thearea calculation expression stored in the area calculation expressionstorage section, the area of a physical block upon division modificationor logical modification can be re-determined.

(7) Since an area and a shape of a physical block calculatedautomatically are automatically evaluated based on the predeterminedvaluation expression and a result of the evaluation is displayed on thedisplay section, the operator who refers to the display section canconfirm the evaluation result of the area and the shape of the physicalblock and determine readily whether or not processing (changing of thedivision condition or the like) corresponding to the evaluation resultshould be performed.

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings inwhich like parts or elements denoted by like reference symbols.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show a floor planning apparatus according to anembodiment of the present invention, and wherein FIG. 1A is a blockdiagram showing a functional construction of the floor planningapparatus and FIG. 1B is a block diagram showing a construction ofseveral components (an area calculation section, a theoretical shapecalculation section and an evaluation section) of the floor planningapparatus;

FIG. 2 is a block diagram showing a hardware construction of the floorplanning apparatus of FIG. 1A;

FIG. 3 is a diagrammatic view showing a circuit construction of an LSIof a floor planning object of the floor planning apparatus of FIG. 1A;

FIG. 4 is a diagrammatic view showing an example of a construction ofsub circuits (divided circuits) obtained by dividing the circuitconstruction of the LSI shown in FIG. 3;

FIG. 5 is a flow chart illustrating a physical block shape determinationprocedure by the floor planning apparatus of FIG. 1A;

FIG. 6 is a schematic illustration showing an example of a screen onwhich a mounting region and physical circuits for realizing sub circuitsare displayed;

FIGS. 7A and 7B are diagrammatic views illustrating an automatic shapeadjustment procedure (shape modification process) of a physical block bythe floor planning apparatus of FIG. 1A;

FIG. 8 is a schematic view showing an example of physical blocks set forindividual sub circuits;

FIG. 9 is a schematic view showing an example wherein the physicalblocks shown in FIG. 8 are arranged in a mounting region using a commonfloor planning technique; and

FIG. 10 is a schematic view showing an example wherein the physicalblocks shown in FIG. 8 are arranged in the mounting region using thefloor planning apparatus of FIG. 1A.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A floor planning apparatus to which the present invention is applied isgenerally constructed such that, in order to mount a design objectcircuit (in the embodiment of the present invention described below, anLSI), it first determines, for each of sub circuits obtained by dividingthe design object circuit, a physical block having an area/shapenecessary to mount the sub circuit in a mounting region and thenarranges such physical blocks in the mounting region. To this end, thefloor planning apparatus is formed from an ordinary processing apparatus(processor or computer) having an arithmetic processing section such asa CPU and storage sections such as a RAM and a ROM.

First, a hardware construction of the floor planning apparatus of theembodiment of the present invention is described with reference to FIG.2.

As seen from FIG. 2, the floor planning apparatus of the presentembodiment includes a logic circuit division editor 21, a keyboardeditor 22, a CPU 23, a display unit (display section) 24, a pointingdevice 25, a data memory 26 and a data bus 27.

The logic circuit division editor 21 divides a logic circuit of an LSIwhich is a design object circuit into a plurality of sub circuits (whichmay be hereinafter referred to as divided circuits). The dividingtechnique will be hereinafter described with reference to FIGS. 3 and 4.A result of the division by the logic circuit division editor 21 isoutputted as design data D1 and sub circuit data D2 and managed by thedata memory 26 as hereinafter described.

The keyboard editor 22 fetches information (an area calculationexpression D3, an evaluation expression D4, shape production parametersD5 and a priority degree D6) from a keyboard not shown operated by anoperator.

The CPU 23 performs various functions in order to realize floor planningby the floor planning apparatus of the present invention as hereinafterdescribed with reference to FIG. 1.

The display unit (display section) 24 displays a construction of adesign object circuit (LSI) to be divided by the logic circuit divisioneditor 21 and displays a result of processing by the CPU 23 [an areaand/or a shape of a physical block (rectangle plotting data D7), anevaluation result and so forth].

The pointing device 25 is, for example, a mouse and is operated by anoperator who refers to the display unit 24 to designate and input apredetermined position (refer to, for example, a position P1 of FIG. 7A)in a mounting region as an arrangement position of a physical block(position data D8).

The data memory 26 stores and manages data necessary to execute floorplanning by the floor planning apparatus of the present embodiment, thatis, design data D1, sub circuit data D2, an area calculation expressionD3, an evaluation expression D4, shape production parameters D5, apriority degree D6, rectangle plotting data D7 and position data D8, andhas such a functional structure as hereinafter described with referenceto FIG. 1.

The data bus 27 interconnects the logic circuit division editor 21,keyboard editor 22, CPU 23, display unit 24, pointing device 25 and datamemory 26 described hereinabove to transmit the data D1 to D8 amongthem.

FIGS. 1A and 1B show the floor planning apparatus as the embodiment ofthe present invention, and FIG. 1A shows a functional construction ofthe floor planning apparatus while FIG. 1B shows a construction ofseveral components (the area calculation section, theoretical shapecalculation section and evaluation section) of the floor planningapparatus.

Referring first to FIG. 1A, the data memory 26 of the floor planningapparatus of the present embodiment includes a part library managementsection 11, a circuit construction management section 12, a physicalblock management section 13 and a mounting region management section 14.

The part library management section (part information storage section)11 stores, for each of minimum circuit units (leaf cells or circuitunits) which form each of sub circuits obtained by dividing a designobject circuit, the number of principal parts (for example, basic cells,areas relating to wiring line regions, pins, networks and fan-outs)which compose the minimum circuit unit.

The circuit construction management section 12 manages groups formedfrom minimum circuit units using logical hierarchies or the like inorder to manage sub circuits (divided circuits) corresponding tophysical circuits, and cooperates with a divided circuit managementsection 13E which will be hereinafter described.

The physical block management section 13 manages information necessaryto determine and/or modify the area/shape of a physical block andincludes an area calculation expression storage section 13A, anevaluation expression storage section 13B, a shape production parameterstorage section 13C, a priority degree management section 13D and adivided circuit management section 13E.

The area calculation expression storage section 13A stores areacalculation expressions (or procedures) to be used for calculation ofnecessary areas for physical blocks. The evaluation expression storagesection 13B stores evaluation expressions for evaluating the areas andshapes of the physical blocks thus calculated and determined. The areacalculation expressions and evaluation expressions to be stored into thestorage sections section 13A and 13B are inputted and set through thekeyboard editor 22.

The shape production parameter storage section 13C stores shapeproduction parameters set in advance for individual physical blocks.Such shape production parameters are required for a theoretical shapecalculation section 34, which will be hereinafter described, tocalculate theoretical shapes (rectangles) of physical blocks andinputted and set through the keyboard editor 22. The shape productionparameters to be set may be {circle around (1)} aspect ratios ofrectangles which compose physical blocks, {circle around (2)} actualdimensions of horizontal or vertical sides of the rectangles whichcompose the physical blocks, and so forth.

The priority degree management section (priority order storage section)13D stores priority degrees (priority order numbers) set in advance forindividual physical blocks. Also the priority degrees are inputted andset through the keyboard editor 22.

The divided circuit management section 13E manages sub circuits (dividedcircuits) corresponding to physical blocks and stores relationshipsbetween groups managed by the circuit construction management section 12described above and physical blocks as rules of default interpretation.While the default interpretation of the divided circuit managementsection 13E is hereinafter described with reference to FIG. 4, use ofthe default interpretation makes it possible to reserve a relationshipbetween a minimum unit circuit newly added by logical modification and aphysical block and makes it possible to re-determine the numbers ofparts of individual physical blocks (sub circuits) without interventionof an operator.

The mounting region management section 14 manages an arrangementcondition of physical blocks in a mounting region and stores a result ofarrangement of a physical block by an arrangement processing section 35(which will be hereinafter described) and a result of modification ofthe shape of a physical block by a shape modification section 36 (whichwill be hereinafter described).

Meanwhile, the CPU 23 of the floor planning apparatus of the presentembodiment functions as a minimum circuit unit recognition section 31, apart number calculation section 32, an area calculation section 33, atheoretical shape calculation section 34, an section arrangementprocessing section 35, a shape modification section 36, an evaluationsection 37, a display control section 38 and a mode setting section 39.It is to be noted that the functions mentioned are actually realized asoperation of the CPU 23 (computer) as a floor planning program which hasbeen installed from a recording medium such as a hard disk, a magnetictape, a floppy disk, an optical disk, a magneto-optical disk or a CD-ROMinto the computer or the like which forms the floor planning apparatusof the present embodiment is read into the RAM or the like and executedby the CPU 23.

The minimum circuit unit recognition section (circuit unit recognitionsection) 31 recognizes minimum circuit units (leaf cells or circuitunits) which compose each of sub circuits based on information stored inthe circuit construction management section 12 and the divided circuitmanagement section 13E (division information by the logic circuitdivision editor 21).

The part number calculation section 32 acquires the numbers of variousparts (for example, basic cells, areas including wiring line regions,pins, networks and fan-outs) which compose a minimum circuit unitrecognized by the minimum circuit unit recognition section 31 from thepart library management section 11 and calculates, for each of parttypes, total numbers of parts in individual sub circuits.

The area calculation section 33 substitutes the total number of partscalculated for each part type by the part number calculation section 32into an area calculation expression read out from the area calculationexpression storage section 13A to calculate and determine the area ofeach physical block. Actually, the area calculation section 33 iscomposed of a calculation expression production section 41 (which willbe hereinafter described) and a calculation processing section 42 (whichwill be hereinafter described) as shown in FIG. 1B. The area calculationsection 33 is constructed such that it re-calculates the area of eachphysical block using an area calculation expression stored in the areacalculation expression storage section 13A upon division change orlogical modification of a design object circuit (LSI). It is to be notedthat the area calculation expression has a total number of parts of eachpart type as a variable as hereinafter described.

The theoretical shape calculation section 34 calculates a theoreticalshape of a physical block based on the area of the physical blockdetermined by the area calculation section 33 and a shape productionparameter set in advance for the physical block. In this instance, theshape production parameter is read out from the shape productionparameter storage section 13C. It is to be noted that, in the presentembodiment, the theoretical shape of a physical block calculated by thetheoretical shape calculation section 34 is limited to a rectangle.

The arrangement processing section (arrangement section) 35 performsprocessing of arranging a physical block at a predetermined position(refer to, for example, the position P1 of FIG. 7A) in a mounting regiondesignated and inputted through the pointing device 25. The physicalblock has an area determined by the area calculation section 33 and hasa theoretical shape (rectangle) calculated by the theoretical shapecalculation section 34. A result of the arrangement by the arrangementprocessing section 35 is stored into the mounting region managementsection 14.

The shape modification section 36 refers to information managed by themounting region management section 14 and reads out, if a physical blockarranged by the arrangement processing section 35 overlaps with anyother physical block arranged already, priority degrees of the physicalblock arranged now and the physical block arranged already from thepriority degree management section 13D, deletes the overlapping portionfrom the physical block which has a lower priority degree andautomatically modifies the shape of the physical block having the lowerpriority degree so that the area of the physical block may be equal tothe area determined by the area calculation section 33 and the physicalblock may not overlap with the other physical block having the higherpriority degree. A result of the modification by the shape modificationsection 36 is stored into the mounting region management section 14.

The evaluation section 37 substitutes an area determined by the areacalculation section 33 and a value of a shape (horizontal or verticaldimension of a rectangle) calculated by the theoretical shapecalculation section 34 or a result of modification by the shapemodification section 36 into an evaluation expression read out from theevaluation expression storage section 13B to evaluate the area and/orthe shape of each physical block. Actually, the evaluation section 37 iscomposed of, as seen from FIG. 1B, a calculation expression productionsection 41 (which will be hereinafter described) and a calculationprocessing section 42 (which will be hereinafter described). It is to benoted that the evaluation expression has, as variables, an areadetermined by the area calculation section 33 and a value of a shape(horizontal or vertical dimension of a rectangle) calculated by thetheoretical shape calculation section 34 or a result of modification bythe shape modification section 36.

The display control section 38 controls the displaying condition of thedisplay unit 24 in order to display the theoretical shape of a physicalblock obtained by the theoretical shape calculation section 34, a resultof modification by the shape modification section 36 or a result ofevaluation by the evaluation section 37 on the display unit 24.

The mode setting section 39 sets, in response to an instruction inputtedthrough the keyboard editor 22 by an operator, whether or not a resultof shape modification/evaluation of an already arranged physical blockby the evaluation section 37 should be displayed. In particular, themode setting section 39 is operable to selectively set, when a physicalblock having a high priority degree is arranged by the arrangementprocessing section 35 and it is discriminated that the physical blockoverlaps with another already arranged physical block, a mode(adjustment mode) in which a shape modification of the already arrangedphysical block and a result of evaluation after such shape modificationare displayed and another mode (inhibition mode) in which display ofsuch shape modification and evaluation result is inhibited.

It is to be noted that the area calculation section 33, theoreticalshape calculation section 34 and evaluation section 37 described aboveare actually formed as a common section having such a circuitconstruction as shown in FIG. 1B. In particular, the CPU 23 has acalculation expression production section 41 and a calculationprocessing section 42 in order to realize the functions of the areacalculation section 33, theoretical shape calculation section 34 andevaluation section 37.

When the calculation expression production section 41 and thecalculation processing section 42 function as the area calculationsection 33, the calculation expression production section 41 produces anexpression which replaces a variable of an area calculation expression(an expression which can describe a variable which represents a numberof principal parts) read out from the area calculation expressionstorage section 13A with an actual number of parts from the part numbercalculation section 32, and the calculation processing section 42determines a result of calculation of the expression produced by thecalculation expression production section 41. Due to the constructiondescribed above, when logical modification or division modification isperformed, an area re-calculation request for a physical block can beautomatically issued in the floor planning apparatus to re-circuit thearea for each physical block.

On the other hand, when the calculation expression production section 41and the calculation processing section 42 function as the theoreticalshape calculation section 34, the calculation expression productionsection 41 produces an expression for determining the lengths of thehorizontal and vertical sides of a rectangle based on a shape productionparameter read out from the shape production parameter storage section13C and an area determined by the area calculation section 33, and thecalculation processing section 42 determines a result of calculation ofthe expression produced by the calculation expression production section41.

Further, when the calculation expression production section 41 and thecalculation processing section 42 function as the evaluation section 37,the calculation expression production section 41 produces an expressionwhich replaces a variable of an evaluation expression read out from thearea calculation expression storage section 13A with an area determinedby the area calculation section 33, a value of a shape (a horizontal orvertical dimension of a rectangle) calculated by the theoretical shapecalculation section 34 or a result of modification by the shapemodification section 36, and the calculation processing section 42determines a result of calculation of the expression produced by thecalculation expression production section 41.

Now, operation of the floor planning apparatus having such aconstruction as described above is described with reference to FIGS. 3to 7.

Here, FIG. 3 shows a circuit construction of an LSI of an object offloor planning (design object circuit) of the floor planning apparatusof the present invention, and FIG. 4 shows an example of a constructionof sub circuits (divided circuits) obtained by dividing the circuitconstruction of the LSI shown in FIG. 3 by means of the logic circuitdivision editor 21.

An LSI of an object of floor planning having, for example, such aconstruction as shown in FIG. 3 is normally designed in a hierarchicalform. In FIGS. 3 and 4, each rectangular block denotes a logicalhierarchy (reference numerals 1 to 6); each circle denotes a leaf cellwhich is a minimum circuit unit; and each straight line between blocksor between a block and a circle denotes a hierarchical relationship.Further, the upper side object of each straight line belongs to arelatively high hierarchy while the lower side object belongs to acomparatively low hierarchy. It is to be noted that each broken linedenotes a component added or deleted by logical modification.

Further, in the present embodiment, a sub region called physical blockin a mounting region is allocated to a circuit block (divided circuit),which is a group of several leaf cells, by the floor planning apparatusdescribed hereinabove with reference to FIGS. 1 and 2. It is to be notedthat one sub circuit corresponds to one physical block.

Upon circuit division, such a circuit diagram as shown in FIG. 3 isdisplayed on the display unit 24 by the logic circuit division editor21, and if an operator who refers to the display unit 24 designates alogical hierarchy or a leaf cell which is an element of the circuitdiagram and instructs the logic circuit division editor 21 of it, thenthe circuit of the floor planning object is divided into sub circuits. Aresult of the division is managed by the circuit construction managementsection 12 and the divided circuit management section 13E as describedhereinabove.

In this instance, by managing the sub circuits while only one subcircuit is mapped with each of all logical hierarchies in advance, a subcircuit to which a logical hierarchy or a leaf cell added is reserved.In particular, it is defined as a rule in default interpretation that anobject of the lower side logic hierarchy belongs to a sub circuit towhich an object of the higher side logical hierarchy belongs.Consequently, a sub circuit to which an object of the lower side logicalhierarchy should belong is reserved.

For example, while an example wherein the circuit shown in FIG. 3 isdivided into four sub circuits A, B, C and D is shown in FIG. 4, in theexample shown in FIG. 4, if a leaf cell is added to the lower side ofthe logical hierarchy 3, then the leaf cell is added to the sub circuitC to which the logical hierarchy 3 belongs, that is, to the physicalblock C. Similarly, a logical hierarchy 6 added to the lower side of thelogical hierarchy 4 and leaf cells belonging to the logical hierarchy 6are added to the sub circuit D to which the logical hierarchy 4 belongs,that is, to the physical block D.

Now, detailed examples of an area calculation expression and anevaluation expression are described.

Where the design object circuit is an LSI, a part which composes a leafcell may be a basic cell, an area including a wiring line region, a pin,a network, a fan-out or the like.

Thus, in the present embodiment, information of such parts is registeredin advance in the part library management section 11, and for each subcircuit, an area number (which corresponds to an area of a wiring lineregion) A of the sub circuit, a total basic cell number B of the subcircuit, a pin number P of the sub circuit, a network number N of thesub circuit and a fan-out number F of the sub circuit are calculatedbased on the information of the part library management section 11 bythe part number calculation section 32. It is to be noted that all ofsuch values are not calculated, but only those values which are requiredto calculate the area (those values which are used as variables of anarea calculation expression) are calculated.

Then, a physical block area S converted with a basic cell area iscalculated using such an area calculation expression (1) or (2) as givenbelow by the area calculation section 33.

For example, where an area calculation expression

S>2.0*B and S<2.2*B  (1)

is given by an operator, at a point of time when modification to thetotal basic area B of a sub circuit is detected, a physical block area Swhich satisfies the expression (1) is calculated by the area calculationsection 33.

On the other hand, where another area calculation expression (2)

S=1.0*B+0.1*F  (2)

is given, a value obtained by adding, to a raw basic cell area B, a 0.1basic cell area as a wiring line region for each fan-out is calculatedas the physical block area S.

It is to be noted here that, while the area calculation expressionswhich involve the total basic area B and the fan-out number F are given,an area can be calculated otherwise using an area calculation expressionwhich includes a combination of more than one of a total basic area B,an area number A, a pin number P, a net number N and a fan-out number Fas variables.

Further, by providing a width (range) to an expression for calculationof a required area S for a physical block to provide a width (range) tothe calculation result S as in the area calculation expression (1)above, frequent modification to the shape of a figure by areare-calculation can be prevented.

In the meantime, while a similar expression to an area calculationexpression can be designated as an evaluation expression, the evaluationsection 37 of the floor planning apparatus of the present embodimentevaluates the shape of a physical block using, for example, anexpression (3) given below. In this instance, the evaluation section 37determines, based on a shape obtained by the theoretical shapecalculation section 34 or a shape after modification obtained by theshape modification section 36, an actual dimension MINW of a minimumwidth of a physical block and a minimum height MINH of the physicalblock, and discriminates whether or not they satisfy the expression (3)

MINW>8.0 μm and MINH>20.0 μm  (3)

to evaluate the physical block. It is to be noted that, while theexpression (3) defines comparison with constants, a number of networksbetween physical blocks with a direction designated or a wiring linedistance may be designated as a variable and inserted into an evaluationexpression.

Now, a physical block shape determination procedure by the floorplanning apparatus of the present embodiment (operation of the floorplanning apparatus of the present embodiment) is described withreference to a flow chart (steps S1 to S14) shown in FIG. 5.

When floor planning is performed, an initial construction of subcircuits or a construction modification of sub circuits is determined byan instruction of an operator (step S1). Particularly, designation datais inputted through the logic circuit division editor 21. At this pointof time, such circuit division as described with reference to FIG. 4 hasbeen completed, and each leaf cell which is a minimum circuit unit of anobject of mounting belongs to one of the sub circuits, and the subcircuits correspond one by one to physical blocks. Further, the physicalblock management section 13 has default values common to all of thephysical blocks set therein as parameters of area calculationexpressions, evaluation values, shapes, priority degrees and so forth.

After an initial construction of sub circuits or a constructionmodification to sub circuits is determined as described above (step S1),the minimum circuit unit recognition section 31 recognizes, based oninformation stored in the circuit construction management section 12 andthe divided circuit management section 13E, minimum circuit units (leafcells) which compose the sub circuits, and then the part numbercalculation section 32 acquires the numbers of parts which compose theminimum circuit units recognized by the minimum circuit unit recognitionsection 31 from the part library management section 11 and calculatestotal numbers of different parts of the sub circuits (required ones ofthe values B, A, P, N and F mentioned hereinabove) (step S2).

Then, processing for all of the physical blocks is started, and it isdiscriminated in step S3 whether or not processing for all of thephysical block is completed. If it is discriminated here that processingfor all of the physical blocks is completed (YES route), then theprocessing comes to an end. However, if a physical block for whichprocessing is not completed remains (NO route), then the controladvances to next step S4.

When the operator requests for modification to a parameter of a physicalblock (YES route from step S4), various parameters (area calculationexpression, evaluation expression, shape, priority degree and so forth)of the physical block management section 13 are modified through thekeyboard editor 22 (step S5).

When no modification to a parameter is to be performed (NO route fromstep S4) or after modification to a parameter is performed in step S5,calculation of the area, the theoretical shape and an evaluationexpression of the physical block is performed and the shape and anevaluation result of the physical block are reported to the operatorthrough the display unit 24 (step S6). In an initial state in which nophysical block is arranged, for example, such a screen as shown in FIG.6 is displayed on the display unit 24. In FIG. 6, an example of a screenon which a mounting area and physical blocks B1 to B10 which realize thesub circuits are displayed is shown. In the display of the initialstate, the physical blocks B1 to B10 are not arranged as yet, and theshapes of the physical blocks B1 to B10 are displayed in theirtheoretical shapes (rectangles).

The operation in step S6 is described in more detail. The areacalculation section 33 substitutes the total numbers of the differentparts calculated by the part number calculation section 32 into an areacalculation expression read out from the area calculation expressionstorage section 13A to calculate and determine the area of each physicalblock. Thereafter, the theoretical shape calculation section 34calculates the theoretical shape (rectangle) based on the area of thephysical block determined by the area calculation section 33 and shapeproduction parameters set in advance for the physical block. Further,the evaluation section 37 substitutes the area determined by the areacalculation section 33 and/or the values of the shape (horizontal orvertical dimensions of the rectangle) calculated by the theoreticalshape calculation section 34 into the evaluation expression read outfrom the evaluation expression storage section 13B to evaluate the areaand/or the shape of each physical block. Then, the display controlsection 38 controls the display unit 24 to display the theoreticalshapes of the physical blocks obtained by the theoretical shapecalculation section 34 and/or the evaluation results by the evaluationsection 37.

The operator who refers to the screen of the display unit 24 uses thepointing device 25 to designate, on the screen of the display unit 24, aphysical block of an object of arrangement and a position in themounting region at which the physical block is desired to be arranged(refer to, for example, the position P1 of FIG. 7A) (step S7). Inresponse to the designation, processing to arrange the designatedphysical block at the designated position is performed by thearrangement processing section 35, and a result of the arrangement isstored into the mounting region management section 14.

Then, it is discriminated whether or not the operator has designated thearrangement position so that the designated physical block may notoverlap with any other physical block arranged already, that is, whetheror not the designated physical block overlaps with any other physicalblock arranged already (step S8). If the designated physical block doesnot overlap (NO route), then the control returns to step S3. On theother hand, if the designated physical block overlaps with another orsecond physical block arranged already (YES route), then it isdiscriminated whether or not the priority degree of the second physicalblock is higher than that of the designated physical block (step S9).The discrimination in step S9 is performed, in the present embodiment,by the shape modification section 36.

If it is discriminated in step S9 that the priority degree of the secondphysical block is higher (YES route), then processing of a loop of stepsS10 and S11 is performed in the inside of the floor planning apparatus(by the shape modification section 36), and at a point of time when thedetermined area by the area calculation section 33 becomes satisfied bythe area (YES route from step S11), evaluation based on an evaluationexpression is performed by the evaluation section 37 and the shape afterthe modification to the physical block and a result of the evaluationare displayed on the display unit 24 by the display control section 38to report them to the operator (step S12). If the operator is notsatisfied with the result of the evaluation, then the control returns tostep S4 or step S7, but if the operator is satisfied, then the controlreturns to step S3.

Here, the processing in steps S10 and S11 (that is, operation of theshape modification section 36) is described in more detail withreference to FIGS. 7A and 7B. It is to be noted that FIGS. 7A and 7Billustrate an automatic shape adjustment procedure (shape modificationprocess) of a physical block by the floor planning apparatus of thepresent embodiment.

The shape modification section 36 automatically modifies the shape ofthe physical block, which has a lower priority degree, arranged by thecurrent operation so that the area of the physical block may becomeequal to the determined area by the area calculation section 33 and thephysical block may not overlap with the physical block of the higherpriority degree.

For example, where physical blocks B1 and B2 are arranged already insuch a manner as shown in FIG. 7A, if it is tried to arrange a furtherphysical block B3 of a theoretical shape such that the left upper cornerof the physical block B3 may be positioned at the designation positionP1 (the left upper corner of the physical block B1), then the physicalblock B3 overlaps with the physical blocks B1 and B2 arranged already.

In this instance, if the priority degree of the physical block B3 islower than those of the physical blocks B1 and B2, then by the functionof the shape modification section 36 of the floor planning apparatus ofthe present embodiment, portions (overlapping regions) overlapping withthe physical blocks B1 and B2 are first deleted from the physical blockB3. Since the deletion of the overlapping regions decreases the area ofthe physical block B3 by an area equal to those of the overlappingregions, in the present embodiment, the shape of the physical block B3is modified such that the physical block B3 is expanded in a directionindicated by an arrow mark A1 in FIG. 7B to secure an area necessary forthe physical block B3 (the determined area by the area calculationsection 33). As a result, the physical block B3 is modified to aphysical block B3′ which has a polygonal shape different from thetheoretical shape (rectangle).

In this manner, if physical blocks are arranged in an overlappingrelationship with each other, the shape modification section 36restricts the overlapping region between them so as to be occupied byonly one of the physical blocks in accordance with the priority degreesof them, subtracts the area of the overlapping region from the physicalblock which is determined not to occupy the overlapping region andautomatically modifies the shape of the physical block so that thephysical block may have a designated area.

It is to be noted that, while FIG. 7B illustrates a case wherein theoperator designates such shape modification that the physical block B3is expanded in the direction indicated by the arrow mark A while thelength of the physical block B3 in the vertical direction in FIG. 7B isfixed, naturally the present invention is not limited to the specificcase, and a physical block may be expanded only in the verticaldirection while the length of the physical block in the horizontaldirection is fixed or may be expanded in both of the horizontaldirection and the vertical direction.

On the other hand, if it is discriminated in step S9 that the secondphysical block has a lower priority degree (NO route), then it isdiscriminated whether or not the mode set by the mode setting section 39is the adjustment mode or the inhibition mode (step S13). If theadjustment mode, that is, the mode in which the second or overlappedphysical block which is influenced by the physical block arranged by theprocessing in step S7 should be adjusted immediately, is set (YES), thenthe shape modification section 36 performs shape adjustment of thephysical block having the lower priority degree (step S14). The shapeadjustment is executed by processing of a loop similar to that of stepsS10 and S11 described hereinabove. Further, similarly as in step S12described above, also evaluation of a result of the shape adjustment isperformed by the evaluation section 37, and a result of the evaluationis displayed on the display unit 24.

It is to be noted that, in the present embodiment, since differentpriority degrees are set for different physical blocks so that any twophysical blocks may not have an equal priority degree, that is, thepriority relationship may not form a loop, upon shape adjustment ofphysical blocks, processing should be proceeded in a descending order interms of the priority degree.

On the other hand, if the inhibition mode is set by the mode settingsection 39 (NO route from step S13), then the control returns to stepS3. Accordingly, while the inhibition mode is set, execution of uselesscalculation upon shape determination during editing is inhibited.

After the position and the shape of one physical block are determined,the control returns to step S3. Then, if it is determined in step S3that there remains no physical block whose shape should be determined(YES route), the processing by the floor planning apparatus of thepresent embodiment comes to an end.

Further, in the floor planning apparatus of the present embodiment, alsowhen a logical modification or a construction modification to a subcircuit occurs or a request for change of the arrangement position of aphysical block is produced by the operator in a condition wherein allphysical blocks are arranged already (refer to step S1), the shape of aphysical block is re-adjusted in accordance with a procedure similar tothat of the flow chart described above with reference to FIG. 5. In thisinstance, the area calculation section 33 automatically performsre-calculation using the area calculation expressions (expressions usedfor calculation of the areas for the individual physical blocks) storedin the area calculation expression storage section 13A to re-calculatethe area.

Further, an example wherein the physical blocks B1 to B10 of variousshapes/areas shown in FIG. 8 are arranged in the mounting region usingthe floor planning apparatus of the present embodiment describedhereinabove is shown in FIG. 10. It is to be noted that the physicalblocks B1 to B10 shown in FIG. 8 and the physical blocks B1 to B10 shownin FIGS. 6, 7A and 7B are produced in different conditions and havedifferent shapes from each other.

In the mounting region shown in FIG. 10, while the physical blocks B1 toB4 are arranged at same positions as those in the example shown in FIG.9, the physical blocks B5 and B6 are arranged at different positionsfrom those in the example shown in FIG. 9. Here, the physical block B5is arranged merely designating a position adjacent the physical block B2and similarly the physical block B6 is arranged merely designating aposition adjacent the physical block B5, and for the arrangement ofthem, the characteristic function of the floor planning apparatus of thepresent embodiment is not used.

A result of arrangement of the physical blocks B7 to B10 using thecharacteristic function of the floor planning apparatus of the presentembodiment after the physical blocks B1 to B6 are arranged in thismanner is shown in FIG. 10.

Referring to FIG. 10, for the physical block B7, an adjacent positionjust below the physical block B4 is designated, and the physical blockB7 is arranged while it is expanded downwardly by an area equal to thearea over which the physical block B7 overlaps with the physical blockB3. Meanwhile, for the physical block B8, a position at which itoverlaps with the physical blocks B2, B5 and B6 is designated, and thephysical block B8 is arranged such that it is expanded downwardly by anarea equal to the area of the portions which overlap with the physicalblocks B2, B5 and B6. Similarly, for the physical block B9, a positionadjacent the physical block B7 and just downwardly adjacent the physicalblock B3 is designated, and the physical block B9 is arranged such thatit is expanded downwardly by an area equal to the area of the portionwhich overlaps with the physical block B8. Furthermore, for the physicalblock B10, a most downward position in the mounting region adjacent thephysical blocks B7 and B9 is designated, and the physical block B10 isarranged such that it is expanded rightwardly by an area equal to thatof portions which overlap with the physical blocks B7 and B9.

As a result, the physical blocks B1 to B10 are arranged very efficiencyin a high density in the mounting region as seen in FIG. 10. Then, anon-used area (refer to a slanting line region or regions) can be formednot in a condition dispersed at a plurality of positions as in FIG. 9,but in the form of a single large region, and a new physical block orblocks can be arranged in the non-used area. The size or shape of thenew physical block or blocks are not subject to such limitation as thatby a common floor planning apparatus, and a physical block or blocks ofvarious types can be arranged and circuit parts can be arranged in ahigh density upon mounting designing.

In this manner, with the floor planning apparatus according to theembodiment of the present invention, for example, where the designobject circuit is an LSI, the areas of physical blocks can be determinedautomatically taking not only basic cells, but also areas includingwiring line regions, pins, networks and fan-outs into consideration. Inshort, physical blocks having areas corresponding sufficiently to actualsub circuits can be produced automatically, and upon mounting designing,circuit parts can be arranged in a high density without giving rise to aproblem in regard to the accuracy.

Further, if circuit division is performed and expressions forcalculation of areas and parameters for production of shapes aredesignated for sub circuits, then since the areas and theoretical shapes(rectangles) of the physical blocks are determined automatically for theindividual sub circuits and displayed on the display unit 24, theoperator can refer to the display unit 24 and confirm the physicalblocks having the areas and the theoretical shapes determinedautomatically.

When physical blocks whose areas and theoretical shapes are determinedare arranged, since overlapping arrangement of a physical block withanother physical block is allowed by setting a priority degree for eachphysical block in advance, while the shape of each block is handled as arectangle at all in operation, a shape (polygon) other than a rectanglecan be provided as an actual shape to the physical block. In thisinstance, the shape of the physical block of the arrangement object isautomatically modified based on the priority degrees of the physicalblocks, information of the overlapped physical block or blocks and thedesignated area of the physical block of the arrangement object.Accordingly, physical blocks are arranged very efficiently in a mountingregion, and also the problem of signal delays can be eliminated withcertainty while satisfying high density arrangement of circuits.

Further, when logical modification in circuit designing occurs, whetheror not modification to the floor plan is required is discriminated byexecuting calculation processing using an area calculation expressionand an evaluation expression registered by the operator in advance, andbased on a result of the discrimination, modification to the area/shapeof a physical block can be performed automatically or can be reported tothe operator.

Further, in the present embodiment, by limiting the theoretical shapesof physical blocks only to rectangles, calculation and determination oftheoretical shapes of physical blocks by the theoretical shapecalculation section 34 can be performed very readily, and the timerequired for calculation can be reduced remarkably.

Furthermore, since the areas and the shapes of the physical blocksdetermined are automatically evaluated using evaluation expressions anda result of the valuation is displayed on the display unit 24, theoperator who refers to the display unit 24 can confirm the evaluationresult of the areas and the shapes of the physical blocks and candetermine very readily whether or not processing (modification to thedivision condition or the like) conforming to the result of theevaluation should be performed.

It is to be noted that the present invention is not limited to theembodiment described above and can be worked in various forms withoutdeparting from the spirit or scope of the present invention.

For example, while, in the embodiment described above, description isgiven of a case wherein the design object circuit is an LSI (Large ScaleIntegration), the present invention is not limited to the specific case,and the present invention can be applied similarly also where the designobject circuit is a circuit of a different type such as a PCB (PrintedCircuit Board). Also in this instance, similar effects to those of theembodiment described above can be achieved.

What is claimed is:
 1. A floor planning apparatus which determines, inorder to mount a design object circuit, for each of sub circuitsobtained by dividing the design object circuit, a physical block havingan area necessary to mount the sub circuit in a mounting region andarranges the physical blocks in the mounting region, comprising: acircuit unit recognition section recognizing circuit units which composeeach of the sub circuits; a part information storage section storing,for each of the circuit units, numbers of parts of different part typeswhich compose the circuit unit; a part number calculation sectionacquiring, for each of the different part types, the numbers of theparts composing the circuit units recognized by said circuit unitrecognition section from said part information storage section andcalculating, for each of the different part types, total numbers of theparts in each of the sub circuits; an area calculation sectioncalculating and determining an area of the physical block based on thetotal numbers of the parts calculated for each of the different parttypes by said part number calculation section; a theoretical shapecalculation section calculating a theoretical shape of the physicalblock based on the area of the physical block determined by said areacalculation section and a shape production parameter set in advance forthe physical block; a display control section causing a display sectionto display the physical block having the theoretical shape obtained bysaid theoretical shape calculation section; an arrangement sectionarranging the physical block having the theoretical shape obtained bysaid theoretical shape calculation section at a designated position inthe mounting region; and a shape modification section deleting, when thephysical block arranged by said arrangement section overlaps withanother one of the physical blocks arranged already, an overlappingportion from one of the arranged physical block and the already arrangedphysical block and modifying the shape of the one physical block whoseoverlapping portion is deleted in such a manner that the one physicalblock has an area equal to the area determined by said area calculationsection and does not overlap with the other one of two physical blocksfrom which the overlapping portion is not deleted.
 2. A floor planningapparatus as claimed in claim 1, further comprising a priority orderstorage section storing a priority order set in advance for theindividual physical blocks, and wherein said shape modification sectiondetermines one of the physical blocks from which the overlapping portionis to be deleted to modify the shape of the physical block based on thepriority order stored in said priority order storage section.
 3. A floorplanning apparatus as claimed in claim 2, further comprising a modesetting section setting a mode in which modification to the shape of anyalready arranged physical block by said shape modification section isinhibited.
 4. A floor planning apparatus as claimed in claim 3, whereinthe theoretical shapes of the physical blocks calculated by said shapemodification section are limited to rectangles.
 5. A floor planningapparatus as claimed in claim 2, wherein the theoretical shapes of thephysical blocks calculated by said shape modification section arelimited to rectangles.
 6. A floor planning apparatus as claimed in claim1, further comprising a mode setting section setting a mode in whichmodification to the shape of any already arranged physical block by saidshape modification section is inhibited.
 7. A floor planning apparatusas claimed in claim 6, wherein the theoretical shapes of the physicalblocks calculated by said shape modification section are limited torectangles.
 8. A floor planning apparatus as claimed in claim 1, whereinthe theoretical shapes of the physical blocks calculated by said shapemodification section are limited to rectangles.
 9. A floor planningapparatus as claimed in claim 1, further comprising an area calculationexpression storage section storing an area calculation expression to beused for calculation of the areas of the physical blocks, and whereinsaid area calculation section re-calculates, upon division modificationor logical modification of the design object circuit, the areas of thephysical blocks using the area calculation expression stored in saidarea calculation expression storage section.
 10. A floor planningapparatus as claimed in claim 1, further comprising: an evaluationexpression storage section for storing an evaluation expression to beused for evaluation of the areas/shapes of the physical blocks; anevaluation section for evaluating the areas/shapes of the physicalblocks based on the evaluation expression stored in said evaluationexpression storage section; and a display control section for causingsaid display section to display a result of the evaluation by saidevaluation section.
 11. A circuit design apparatus, comprising: anarrangement section arranging a physical block having a calculatedtheoretical shape at a designated position in a mounting region; and ashape modification section deleting, when the physical block arranged bysaid arrangement section overlaps with another one of the physicalblocks arranged already, an overlapping portion from one of a newlyarranged physical block and the already arranged physical block andmodifying the shape of the one physical block whose overlapping portionis deleted in such a manner that the one physical block has an areaequal to an area based on total numbers of parts calculated for each ofdifferent part types and does not overlap with the other one of twophysical blocks from which the overlapping portion is not deleted.
 12. Afloor planning method for determining, in order to mount a design objectcircuit, for each of sub circuits obtained by dividing the design objectcircuit, a physical block having an area necessary to mount the subcircuit in a mounting region and arranging the physical blocks in themounting region, comprising: recognizing, for each of the sub circuits,circuit units which compose the sub circuit; acquiring, for each of thecircuit units recognized, numbers of parts of different part types whichcompose the circuit unit and calculating, for each of the different parttypes, total numbers of the parts in each of the sub circuits;calculating and determining an area of the physical block based on thetotal numbers of the parts calculated for each of the different parttypes; calculating a theoretical shape of the physical block based onthe area of the physical block and a shape production parameter set inadvance for the physical block; causing a display section to display thephysical block having the calculated theoretical shape; and deleting,when the physical block having the calculated theoretical shape isarranged at a designated position in the mounting region, if thephysical block overlaps with another one of the physical blocks arrangedalready, an overlapping portion from one of a newly arranged physicalblock and the already arranged physical block and modifying the shape ofthe one physical block whose overlapping portion is deleted in such amanner that the one physical block has an area equal to a determinedarea and does not overlap with the other one of two physical blocks fromwhich the overlapping portion is not deleted.
 13. A floor planningmethod as claimed in claim 12, wherein one of the physical blocks fromwhich the overlapping portion is to be deleted to modify the shape ofthe physical block is determined based on a priority order set inadvance for the individual physical blocks.
 14. A circuit design method,comprising: arranging a physical block having a calculated theoreticalshape at a designated position in a mounting region; and deleting, whenthe physical block arranged by said arrangement section overlaps withanother one of the physical blocks arranged already, an overlappingportion from one of a newly arranged physical block and the alreadyarranged physical block and modifying the shape of the one physicalblock whose overlapping portion is deleted in such a manner that the onephysical block has an area equal to an area based on total numbers ofparts calculated for each of different part types and does not overlapwith the other one of two physical blocks from which the overlappingportion is not deleted.
 15. A computer-readable recording medium havinga floor planning program recorded thereon for causing, in order to mounta design object circuit, a computer to determine, for each of subcircuits obtained by dividing the design object circuit, a physicalblock having an area necessary to mount the sub circuit in a mountingregion and arrange the physical blocks in the mounting region, saidfloor planning program causing said computer to operate as: a circuitunit recognition section recognizing circuit units which compose each ofthe sub circuits; a part number calculation section acquiring, for eachof the different part types, numbers of parts composing the circuitunits recognized by said circuit unit recognition section andcalculating, for each of the different part types, total numbers of theparts in each of the sub circuits; an area calculation sectioncalculating and determining an area of the physical block based on thetotal numbers of the parts calculated for each of the different parttypes by said part number calculation section; a theoretical shapecalculation section calculating a theoretical shape of the physicalblock based on the area of the physical block determined by said areacalculation section and a shape production parameter set in advance forthe physical block; a display control section causing a display sectionto display the physical block having the theoretical shape obtained bysaid theoretical shape calculation section; an arrangement sectionarranging the physical block having the theoretical shape obtained bysaid theoretical shape calculation section at a designated position inthe mounting region; and a shape modification section deleting, when thephysical block arranged by said arrangement section overlaps withanother one of the physical blocks arranged already, an overlappingportion from one of a newly arranged physical block and the alreadyarranged physical block and modifying the shape of the one physicalblock whose overlapping portion is deleted in such a manner that the onephysical block has an area equal to the area determined by said areacalculation section and does not overlap with the other one of twophysical blocks from which the overlapping portion is not deleted.
 16. Acomputer-readable recording medium having a floor planning programrecorded thereon as claimed in claim 15, wherein, when said floorplanning program causes said computer to function as said shapemodifications sections, said floor planning programs causes saidcomputer to determined one of the physical block from which theoverlapping portion is to be deleted to modify the shaped of thephysical block based on a priority order set in advance for theindividual physical blocks.
 17. A computer readable storage medium,storing a program containing a circuit design method, the programinstructing a computer to perform: arranging a physical block having acalculated theoretical shape at a designated position in a mountingregion; and deleting, when the physical block arranged by saidarrangement section overlaps with another one of the physical blocksarranged already, an overlapping portion from one of a newly arrangedphysical block and the already arranged physical block and modifying theshape of the one physical block whose overlapping portion is deleted insuch a manner that the one physical block has an area equal to an areabased on total numbers of parts calculated for each of different parttypes and does not overlap with the other one of two physical blocksfrom which the overlapping portion is not deleted.